The vast improvements of the medical imaging and localization technology over recent years has brought a challenge to physics and computer technology to extend the capabilities of computerized treatment planning and optimization. The current and final release has been validated for clinical use on Windows NT/2000 platforms. The Windows NT version is now the standard clinical treatment planning platform and the Macintosh platform will be discontinued. The NT version is based on the OpenGL graphics engine, which provides superior 3D image display and manipulation. A new interactive algorithm has been developed for image fusion using real-time volume rendering. Although this is currently used with CT and MRI images, any image set can be fused. File/image import and export in RTOG format has been implemented for communication with Lawerence Livermore National Laboratory. Import and export in DICOM-RT format will be implemented in FY-2001 for communication with the Telesynergy Radiological Imaging Workstation Project in conjunction with CIT. Communication with LLNL permits a clinical research project using their PEREGRINE Monte Carlo dose calculation engine. This engine will also be used to validate the photon dose calculation methodology of the NIH-TPS. Also planned is the use of the TPS for stereotactic radiosurgery/radiotherapy (SRS/SRT) as well as Intensity Modullated Radiotherapy (IMRT). A separate program for brachytherapy has been developed, which performs calculations using the AAPM TG-43 formalism. Modifications to the angular and radial dose functions have been made to permit treatment planning for intravascular brachytherapy. We are in the process of negoating a CRADA for further development of the system, including dose optimization and incorporating real-time volume rendering technology.